Due to which characteristic of sound does a sound become thick (grave) or thin (shrill)?

The characteristic of sound that determines whether it is perceived as thick (grave) or thin (shrill) is pitch. Pitch is directly related to the frequency of the sound wave: lower frequencies result in lower pitches, producing a thick or grave sound, while higher frequencies result in higher pitches, producing a thin or shrill sound. For example, the deep sound of a bass drum has a low pitch, making it sound thick or grave, whereas the high-pitched sound of a whistle has a high pitch, making it sound thin or shrill. This property is crucial in music and acoustics, influencing how different sounds are perceived and categorized. Pitch enables us to distinguish between different musical notes and the tonal qualities of various instruments and voices. Hence, the correct answer is [B] Pitch.